Introduction to C ++ builder VCL library functions

1. Borland C ++ builder VCL memory management functions

1. allocmem
Allocate memory blocks of specified bytes in the queue and initialize each allocated byte to 0. The function prototype is as follows:
Void * _ fastcall allocmem (Cardinal size );

2. sysfreemem
Release the specified memory block. The function prototype is as follows:
Int _ fastcall sysfreemem (void * P );

3. sysreallocmem
The memory specified by the reallocation parameter size is required. The function prototype is as follows:
Void * _ fastcall sysreallocmem (void * P, int size );

　　Ii. Borland C ++ builder VCL file operation functions

1. fileopen
Open the specified file. If a positive number is returned, the operation is successful. If the returned value is-1, the operation fails. The function prototype is as follows:
Int _ fastcall fileopen (const system: ansistring filename, int mode );

2. filecreate
Create a new file with the specified file name. If a positive number is returned, the operation is successful, and the returned value is the file handle. If the returned value is-1, the operation fails. The function prototype is as follows:
Int _ fastcall filecreate (const system: ansistring filename );

3. fileread
The function returns the actual number of bytes read from the file to the buffer. The function prototype is as follows;
Int _ fastcall fileread (INT handle, void * buffer, int count );

4. filewrite
Write the data in the buffer to the current location of the specified file. If the operation succeeds, the function returns the number of bytes actually written. If the returned value is-1, the operation produces an error, the function prototype is as follows:
Int _ fastcall filewrite (INT handle, const void * buffer, int count );

5. FileSeek
Adjust the file pointer to the new location. If the operation succeeds, the new file location is returned. If the operation fails, the function returns-1. The function prototype is as follows:
Int _ fastcall FileSeek (INT handle, int offset, int origin );

6. fileclose
Close the specified file. The function prototype is as follows:
Void _ fastcall fileclose (INT handle );

7. fileage
Returns the time tag of the specified file. If the operation fails,-1 is returned. The function prototype is as follows:
Int _ fastcall fileage (const system: ansistring filename );

8. fileexists
Used to test whether the specified file exists. If the returned result is true or false, the function prototype is as follows:
Bool _ fastcall fileexists (const system: ansistring filename );

9. filegetdate
Returns the DOS time tag of the specified file. If the operation fails, it is near-1. The function prototype is as follows:
Int _ fastcall filegetdate (INT handle );

10. filesetdate
Change the DOS time tag of the specified file. If the operation succeeds, 0 is returned. Otherwise, the error code is returned. The function prototype is as follows:
Int _ fastcall filesetdate (INT handle, int age );

11. filegetattr
Returns the properties of the specified file. If the operation fails, the function returns-1. The function prototype is as follows;
Int _ fastcall filegetattr (const system: ansistring filename );

12. filesetattr
Change the attribute parameters of the specified file. If the operation is successful, 0 is returned. The function prototype is as follows;
Int _ fastcall filesetattr (const system: ansistring filename, int ATTR );

13. findfirst
Search for files that meet the specified attribute parameters in the specified file directory. If the files that meet the condition are found successfully,
The function returns 0. Otherwise, the function returns an error code. The function prototype is as follows:
Int _ fastcall findfirst (const system: ansistring path, int ATTR, tsearchrec &; f );

14. findnext
Continue to search for the file with the attribute parameters specified by findfirst. If the file is found successfully, the function returns 0; otherwise, the function returns an error code. The function prototype is as follows:
Int _ fastcall findnext (tsearchrec &; f );

15. findclose
Release the memory resources applied for by the findfirst operation. The function prototype is as follows:
Void _ fastcall findclose (tsearchrec &; f );

16. deletefile
Delete the specified file from the computer disk. If the operation succeeds, the function returns true. The function prototype is as follows:
Bool _ fastcall deletefile (const ansistring filename );

17. renamefile
Change the name of the specified file. If the operation succeeds, the function returns true. The function prototype is as follows:
Bool _ fastcall renamefile (const ansistring oldname, const ansistring newname );

18. changefileext
Modify the extension of the specified file. The function prototype is as follows:
Ansistring _ fastcall changefileext (const ansistring filename, const ansistring extension );

19. extractfilepath
Returns the working path of the specified file. The function prototype is as follows:
Ansistring _ fastcall extractfilepath (const ansistring filename );

20. extractfiledir
Returns the working directory of the specified file. The function prototype is as follows:
Ansistring _ fastcall extractfiledir (const ansistring filename );

21. extractfiledrive
Returns the drive of the specified file. The function prototype is as follows:
Ansistring _ fastcall extractfiledrive (const ansistring filename );

22. extractfilename
Returns the name and extension of the specified file. The function prototype is as follows:
Ansistring _ fastcall extractfilename (const ansistring filename );

23. extractfileext
Returns the extension of the specified file. The function prototype is as follows:
Ansistring _ fastcall extractfileext (const ansistring filename );

Iii. Borland C ++ builder VCL disk management functions

1. diskfree
Returns the remaining space of the specified disk. If the operation succeeds, returns the remaining disk space. If the operation fails,-1 is returned. The function prototype is as follows:
Int _ fastcall diskfree (byte drive );

2. disksize
Return the space of the specified disk. If the operation succeeds, return the disk space. If the operation fails, return-1. The function prototype is as follows:
Int _ fastcall disksize (byte drive );

3. getcurrentdir
Return to the current working directory. The function prototype is as follows:
Ansistring _ fastcall getcurrentdir ();

4. setcurrentdir
Set the current working directory. If the operation is successful, the system returns true. The function prototype is as follows:
Bool _ fastcall setcurrentdir (const ansistring DIR );

5. createdir
Create a new directory. If the operation is successful, true is returned. Otherwise, false is returned. The function prototype is as follows:
Bool _ fastcall createdir (const ansistring DIR );

6. removedir
Delete the specified directory. If the operation is successful, the system returns true. Otherwise, the system returns false. The function prototype is as follows:
Bool _ fastcall removedir (const ansistring DIR );

　　Iv. Borland C ++ builder VCL string functions

1. uppercase
Converts a specified ansistring to an uppercase string. The function prototype is as follows:
Ansistring _ fastcall uppercase (const ansistring S );

2. lowercase
Converts the specified ansistring string to lowercase. The function prototype is as follows:
Ansistring _ fastcall lowercase (const ansistring S );

3. comparestr
Compare two ansistring strings. The function prototype is as follows:
Int _ fastcall comparestr (const ansistring S1, const ansistring S2 );

4. comparetext
Compare two ansistring strings. The function prototype is as follows:
Int _ fastcall comparetext (const ansistring S1, const ansistring S2 );

5. strlen
Returns the string length. The function prototype is as follows:
Cardinal _ fastcall strlen (const char * Str );

6. strend
Returns the pointer to the end of a string. The function prototype is as follows:
Char * _ fastcall strend (const char * Str );

7. strmove
Copy a specified number of characters from the source string to the target string. The function prototype is as follows:
Char * _ fastcall strmove (char * DEST, const char * Source, Cardinal count );

8. strcopy
Copy the source string to the target string. The function prototype is as follows:
Char * _ fastcall strcopy (char * DEST, const char * Source );

9. strecopy
Copy the source string to the destination string and return the pointer to the end of the destination string. The function prototype is as follows:
Char * _ fastcall strecopy (char * DEST, const char * Source );

10. strlcopy
Copy the specified number of characters in the source string to the destination string and return the destination string pointer. The function prototype is as follows:
Char * _ fastcall strlcopy (char * DEST, const char * Source, Cardinal maxlen );

11. strpcopy
Copy the source string of the ansistring type to the destination string and return the destination string pointer. The function prototype is as follows:
Char * _ fastcall strpcopy (char * DEST, const ansistring source );

12. strplcopy
Copy a specified number of characters from the source string (ansistring type) to the destination string and return the destination string.
Pointer. The function prototype is as follows:
Char * _ fastcall strplcopy (char * DEST, const ansistring source, Cardinal maxlen );

13. strcat
Connect two strings and return the destination string pointer. The function prototype is as follows:
Char * _ fastcall strcat (char * DEST, const char * Source );

14. strlcat
Connect a specified number of source strings to the destination string and return the destination string pointer. The function prototype is as follows:
Char * _ fastcall strlcat (char * DEST, const char * Source, Cardinal maxlen );

15. strcomp
When two strings are compared, the comparison result is returned. The function prototype is as follows:
Int _ fastcall strcomp (const char * str1, const char * str2 );

16. stricomp
The two strings are compared (case-insensitive) and the comparison result is returned. The function prototype is as follows:
Int _ fastcall stricomp (const char * str1, const char * str2 );

17. strlcomp
Compare two strings with a specified number of characters. The function prototype is as follows:
Int _ fastcall strlcomp (const char * str1, const char * str2, Cardinal maxlen );

18. strscan
Search for specific characters in the specified string and return the pointer of the First Specific Character in the string. The function prototype is as follows:
Char * _ fastcall strscan (const char * STR, char CHR );

19. strrscan
Search for specific characters in the specified string and return the pointer of the last specific character in the string. The function prototype is as follows:
Char * _ fastcall strrscan (const char * STR, char CHR );

20. strpos
Search for the substring specified by str2 in the string specified by strl, and return the pointer to the first substring of str2 in str2. The function prototype is as follows:
Char * _ fastcall strpos (const char * str1, const char * str2 );

21. strupper
Converts a string to uppercase. The function prototype is as follows:
Char * _ fastcall strupper (char * Str );

22. strlower
Converts a string to lowercase. The function prototype is as follows:
Char * _ fastcall strlower (char * Str );

23. strpas
Converts a specified string to an ansistring. The function prototype is as follows:
Ansistring _ fastcall strpas (const char * Str );

24. stralloc
Allocate the specified bytes of memory to the string and return the memory pointer. The function prototype is as follows:
Char * _ fastcall stralloc (Cardinal size );

25. strbufsize
Returns the memory size pointed to by * Str. The function prototype is as follows:
Cardinal _ fastcall strbufsize (const char * Str );

26. strnew
Allocate space for the specified string in the heap and copy the string to the space. The function prototype is as follows:
Char * _ fastcall strnew (const char * Str );

V. Borland C ++ builder VCL numeric Conversion Function

1. inttostr
Converts an integer to an ansistring. The function prototype is as follows:
Ansistring _ fastcall inttostr (INT value );

2. inttohex
Converts an integer to a hexadecimal string. The function prototype is as follows:
Ansistring _ fastcall inttohex (INT value, int digits );

3. strtoint
The ansistring is converted to an integer. If the ansistring cannot be converted, an econverterror exception occurs,
The function prototype is as follows:
Int _ fastcall strtoint (const ansistring S );

4. strtointdef
Converts an ansistring string to a numeric value. The function prototype is as follows:
Int _ fastcall strtointdef (const system: ansistring S, int default );

5. floattostr
Converts a floating point number to an ansistring. The function prototype is as follows:
Ansistring _ fastcall floattostr (Extended value );

6. strtofloat
Converts an ansistring string to a floating point value. The function prototype is as follows:
Extended _ fastcall strtofloat (const ansistring S );

7. floattostrf
Converts a floating point number to an ansistring in the specified format. The function prototype is as follows:
Ansistring _ fastcall floattostrf (Extended value, tfloatformat format, int precision, int digits );

　　Vi. Borland C ++ builder VCL Time Functions

1. Date
The returned tdatetime object contains the current year, month, and day information. The function prototype is as follows:
System: tdatetime _ fastcall date (void );

2. Time
The returned tdatetime object contains the current time information. The function prototype is as follows:
System: tdatetime _ fastcall time (void );

3. Now
Returns the tdatetime object to obtain the current date and time information. The function prototype is as follows:
System: tdatetime _ fastcall now (void );

4. datetimetostring
Converts a tdatetime object to a string object in the specified format. The function prototype is as follows:
Void _ fastcall datetimetostring (ansistring &; Result, const ansistring format, system: tdatetime datetime );

5. datetostr
Convert the tdatetime object (including the current year, month, and day information) to a string object. The function prototype is as follows:
Ansistring _ fastcall datetostr (System: tdatetime date );

6. timetostr
Converts the current date to a string object. The function prototype is as follows:
Ansistring _ fastcall timetostr (System: tdatetime time );

7. datetimetostr
Convert a tdatetime object to a string object. The function prototype is as follows:
Ansistring _ fastcall datetimetostr (System: tdatetime datetime );

8. strtodate
Converts a String object to a year, month, or day object. The function prototype is as follows:
System: tdatetime _ fastcall strtodate (const ansistring S );

9. strtotime
Converts a String object to a time object. The function prototype is as follows:
System: tdatetime _ fastcall strtotime (const ansistring S );

10. strtodatetime
Converts a String object to an object of year, month, day, and time. The function prototype is as follows:
System: tdatetime _ fastcall strtodatetime (const ansistring S );

11. datetimetosystemtime
Convert the tdatetime object to the operating system time. The function prototype is as follows:
Void _ fastcall datetimetosystemtime (System: tdatetime datetime, _ systemtime &; systemtime );

12. systemtimetodatetime
Convert the operating system time to a tdatetime object. The function prototype is as follows:
System: tdatetime _ fastcall systemtimetodatetime (const _ systemtime &; systemtime );