fputs — put a string on a stream
#include <stdio.h>
int fputs(const char *restrict s, FILE *restrict stream);
[CX] 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 POSIX.1-2024 defers to the ISO C standard.The fputs() function shall write the null-terminated string pointed to by s to the stream pointed to by stream. The terminating null byte shall not be written.
[CX] The last data modification and last file status change timestamps of the file shall be marked for update between the successful execution of fputs() and the next successful completion of a call to fflush() or fclose() on the same stream or a call to exit() or abort().
Upon successful completion, fputs() shall return a non-negative number. Otherwise, it shall return EOF, set an error indicator for the stream, [CX] and set errno to indicate the error.
Refer to fputc .
Printing to Standard Output
The following example gets the current time, converts it to a string using localtime() and asctime(), and prints it to standard output using fputs(). It then prints the number of minutes to an event for which it is waiting.
#include <time.h> #include <stdio.h> ... time_t now; int minutes_to_event; ... time(&now); printf("The time is "); fputs(asctime(localtime(&now)), stdout); printf("There are still %d minutes to the event.\n", minutes_to_event); ...
The puts() function appends a <newline> while fputs() does not.
This volume of POSIX.1-2024 requires that successful completion simply return a non-negative integer. There are at least three known different implementation conventions for this requirement:
Return a constant value.
Return the last character written.
Return the number of bytes written. Note that this implementation convention cannot be adhered to for strings longer than {INT_MAX} bytes as the value would not be representable in the return type of the function. For backwards-compatibility, implementations can return the number of bytes for strings of up to {INT_MAX} bytes, and return {INT_MAX} for all longer strings.
The fputs() function is one whose source code was specified in the referenced The C Programming Language. In the original edition, the function had no defined return value, yet many practical implementations would, as a side-effect, return the value of the last character written as that was the value remaining in the accumulator used as a return value. In the second edition of the book, either the fixed value 0 or EOF would be returned depending upon the return value of ferror(); however, for compatibility with extant implementations, several implementations would, upon success, return a positive value representing the last byte written.
None.
2.5 Standard I/O Streams , fopen , putc , puts
XBD <stdio.h>
First released in Issue 1. Derived from Issue 1 of the SVID.
Extensions beyond the ISO C standard are marked.
The fputs() prototype is updated for alignment with the ISO/IEC 9899:1999 standard.
Changes are made related to support for finegrained timestamps.
POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0170 [174,412], XSH/TC1-2008/0171 [412], and XSH/TC1-2008/0172 [14] are applied.
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