First day----fclose

http://blog.csdn.net/qin9r3y/article/details/8652207

/* Learn about the C language storage */

The previous section fopen the return value of the FILE * Type pointer is placed on the heap

If the return value of a function is a pointer and has an inverse operation, then the pointer to the return value must be on the heap

If the return value of a function is a pointer without an inverse operation, then the pointer to the return value may be on the heap or in the static area

int fclose (FILE *FP);

Parameters: Flow

Return value: Success 0, failed EOF defaults to-1.

#include <stdio.h>#include<stdlib.h>#include<errno.h>#include<string.h>intMainvoid) {FILE*FP; FP= fopen ("Temp","w+"); if(fp = =NULL) {        //fprintf (stderr, "fopen () failed.        errno =%d\n ", errno); //perror ("fopen ()");fprintf (stderr,"fopen ():%s\n", Strerror (errno)); Exit (1); } printf ("ok!");    Fclose (FP); Exit (0);}

View Code

Run Result: Successfully created file and print OK.

To view the file permissions created:

-rw-rw-r--: 0666 & ~umask (0002);//purpose in order to produce files that are too loose

There is an upper limit to the flow resources used by the test

#include <stdio.h>#include<stdlib.h>#include<errno.h>#include<string.h>intMainvoid) {FILE*FP; intcount;  while(1) {FP= fopen ("Temp","w+"); if(fp = =NULL) {            //fprintf (stderr, "fopen () failed. errno =%d\n ", errno);Perror ("fopen ()");  Break ; }} printf ("count =%d\n", Count); Exit (0);}

To view the results of the output:

1021

Command: ULIMIT-A View---Open files 1021+stdin+stderr+stdout ==1024

First day----fclose