fgetpos
From cppreference.com
| Defined in header
<stdio.h>
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| (until C99) | ||
| (since C99) | ||
Obtains the file position indicator for the file stream stream and stores it in pos.
Contents |
[edit] Parameters
| stream | - | file stream to examine |
| pos | - | pointer to a fpos_t object to store the file position indicator to |
[edit] Return value
0 upon success, nonzero value otherwise.
[edit] Example
fgetpos with error checking
Run this code
#include <stdio.h> #include <stdlib.h> int main(void) { /* Prepare an array of f-p values. */ #define SIZE 5 double A[SIZE] = {1.,2.,3.,4.,5.}; /* Write array to a file. */ FILE * fp = fopen("test.bin", "wb"); fwrite(A,sizeof(double),SIZE,fp); fclose (fp); /* Read the f-p values into array B. */ double B[SIZE]; fp = fopen("test.bin","rb"); fpos_t pos; if (fgetpos(fp,&pos) != 0) /* current position: start of file */ { perror("fgetpos()"); fprintf(stderr,"fgetpos() failed in file %s at line # %d\n", __FILE__,__LINE__-3); exit(EXIT_FAILURE); } int ret_code = fread(B,sizeof(double),1,fp); /* read one f-p value */ /* current position: after reading one f-p value */ printf("%.1f\n", B[0]); /* print one f-p value */ fsetpos(fp,&pos); /* reset current position to start of file */ ret_code = fread(B,sizeof(double),1,fp); /* reread first f-p value */ printf("%.1f\n", B[0]); /* print one f-p value */ return EXIT_SUCCESS; }
Output:
1.0 1.0
[edit] References
- C11 standard (ISO/IEC 9899:2011):
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- 7.21.9.1 The fgetpos function (p: 336)
- C99 standard (ISO/IEC 9899:1999):
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- 7.19.9.1 The fgetpos function (p: 302)
- C89/C90 standard (ISO/IEC 9899:1990):
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- 4.9.9.1 The fgetpos function
[edit] See also
| returns the current file position indicator (function) |
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| moves the file position indicator to a specific location in a file (function) |
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| moves the file position indicator to a specific location in a file (function) |
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C++ documentation for fgetpos
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