The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.
A newer edition of this document exists here

NAME

fgets - get a string from a stream

SYNOPSIS

#include <stdio.h>

char *fgets(char *restrict
s, int n, FILE *restrict stream);

DESCRIPTION

[CX] [Option Start] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard. [Option End]

The fgets() function shall read bytes from stream into the array pointed to by s, until n-1 bytes are read, or a <newline> is read and transferred to s, or an end-of-file condition is encountered. The string is then terminated with a null byte.

[CX] [Option Start] The fgets() function may mark the st_atime field of the file associated with stream for update. The st_atime field shall be marked for update by the first successful execution of fgetc(), fgets(), fgetwc(), fgetws(), fread(), fscanf(), getc(), getchar(), gets(), or scanf() using stream that returns data not supplied by a prior call to ungetc() or ungetwc(). [Option End]

RETURN VALUE

Upon successful completion, fgets() shall return s. If the stream is at end-of-file, the end-of-file indicator for the stream shall be set and fgets() shall return a null pointer. If a read error occurs, the error indicator for the stream shall be set, fgets() shall return a null pointer, [CX] [Option Start]  and shall set errno to indicate the error. [Option End]

ERRORS

Refer to fgetc().


The following sections are informative.

EXAMPLES

Reading Input

The following example uses fgets() to read each line of input. {LINE_MAX}, which defines the maximum size of the input line, is defined in the <limits.h> header.

#include <stdio.h>
...
char line[LINE_MAX];
...
while (fgets(line, LINE_MAX, fp) != NULL) {
...
}
...

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

fopen(), fread(), gets(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 6

Extensions beyond the ISO C standard are marked.

The prototype for fgets() is changed for alignment with the ISO/IEC 9899:1999 standard.

End of informative text.

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