Linux C, file read and write functions

The C standard library provides a very large number of functions for reading and writing files, and most functions are declared in stdio.h.

Fread/fwrite,fgets/fputs,fgetchar/fputchar,fprintf/fscanf ........

These function prototype declarations are all in stdio.h, as follows:

size_t fread (void *ptr, size_t size, size_t nmemb, FILE *stream);

size_t fwrite (const void *ptr, size_t size, size_t nmemb,file *stream);

int fgetc (FILE *stream);

Char *fgets (char *s, int size, FILE *stream);

int getc (FILE *stream);

int GetChar (void);

int ungetc (int c, FILE *stream);

Whether you are writing to a file or reading from a stream of files, you must first open the file, and then close the open file when you are finished.

To prevent the pointer from becoming a wild pointer, you should also point the file pointer to null.

FILE *fopen (const char *pathname, const char *mode);

FILE *fdopen (int fd, const char *mode);

File *freopen (const char *pathname, const char *mode, file *stream);

The security version of the fopen function is fopen_s (FILE *stream,char *filename,char *mode), which is used before the macro

Fileutil.h

1 #ifndef __fileutil_h2 3 #define__fileutil_h4 5#include <stdio.h>6 7FILE *open_file (Const Char*file,Const Char*mode);8 9 voidREAD0 (Const Char*file);Ten  One voidRead1 (Const Char*file); A  - voidRead2 (Const Char*file); -  the voidWrite1 (Const Char*file); -  - #endif

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Fileutil.c

1 /*2 3  * =====================================================================================4 5 * FILENAME:FILEUTIL.C6 7 * Description:8 9 * version:1.0Ten  One * created:2017 April 13 09:38 23 seconds A  - * Revision:none -  the * COMPILER:GCC -  - * Author:your NAME (), -  + * Organization: -  +  * ===================================================================================== A  at  */ -  -#include <stdio.h> -  -#include <stdlib.h> -  in#include <string.h> -  to#include"fileutil.h" +  -   the  *FILE * $ Panax NotoginsengOpen_file (Const Char*file,Const Char*mode) -  the { +  AFILE *FP; the  +  if(! (fp =fopen (File,mode))) { -  $Perror ("Open File Error"); $  -Exit (-1); -  the  } - Wuyi  returnFP; the  - } Wu  -   About  $ voidREAD0 (Const Char*file) -  - { -  AFile *FP = open_file (file,"R"); +  the  CharBuf[bufsiz] = {0}; -  $UnsignedLongt =0; the  the  //int tmp = fread (BUF,1,20,FP); the  the  //printf ("Read%d bytes\n", TMP); -  in  //printf ("Read buf from%s is%s\n", file,buf); the  the   while(t = fread (BUF,1,192, fp))! =0){ About  theprintf"%s\n", buf); the  theBzero (&buf,sizeof(BUF)); +  -  } the Bayi  if(fclose (fp)! =0) Perror ("Close File Error"); the  the } -  -   the  the voidRead1 (Const Char*file) the  the { -  theFile *FP = open_file (file,"R"); the  the  Char*buf;94  thesize_t n =0; the  the   while((n = getline (&AMP;BUF,&AMP;N,FP))! = (size_t)-1){98  Aboutprintf"%s", buf); - 101Bzero (BUF,sizeof(BUF));102 103  }104  the  //if (buf) free (BUF);106 107  if(fclose (fp)! =0) Perror ("Close File Error");108 109 }  the 111   the 113 voidRead2 (Const Char*file) the  the { the 117File *FP = open_file (file,"R");118 119  CharBuf[bufsiz] =""; - 121   while(Fgets (BUF,BUFSIZ,FP)) {122 123printf"%s", buf);124  the bzero (buf,bufsiz);126 127  } - 129  if(fclose (fp)! =0) Perror ("Close File Error"); the 131 } the 133  134 135 /*not yet implemented*/136 137 voidWrite1 (Const Char*file)138 139 { $ 141File *FP = open_file (file,"a+t");142 143  if(fclose (fp)! =0) Perror ("Close File Error");144 145}

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Linux C, file read and write functions