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putchar - cppreference.com

From cppreference.com

Writes a character ch to stdout. Internally, the character is converted to unsigned char just before being written.

Equivalent to putc(ch, stdout).

Parameters

ch - character to be written

Return value

On success, returns the written character.

On failure, returns EOF and sets the error indicator (see ferror()) on stdout.

Example

Shows putchar with error checking

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    int ret_code = 0;
    for (char c = 'a'; (ret_code != EOF) && (c != 'z'); c++)
        ret_code = putchar(c);
 
    // Test whether EOF was reached.
    if (ret_code == EOF && ferror(stdout))
    {
        fprintf(stderr, "putchar() failed in file %s at line # %d\n",
                __FILE__, __LINE__ - 6);
        perror("putchar()");
        exit(EXIT_FAILURE);
    }
    putchar('\n');

    // putchar return value is not equal to the argument
    int r = 0x1070;
    printf("\n0x%x\n", r);
    r = putchar(r);
    printf("\n0x%x\n", r);
}

Output: 

abcdefghijklmnopqrstuvwxy

0x1070
p
0x70

References

  • C23 standard (ISO/IEC 9899:2024):
  • 7.21.7.8 The putchar function (p: TBD)
  • C17 standard (ISO/IEC 9899:2018):
  • 7.21.7.8 The putchar function (p: TBD)
  • C11 standard (ISO/IEC 9899:2011):
  • 7.21.7.8 The putchar function (p: 333)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.19.7.9 The putchar function (p: 299)
  • C89/C90 standard (ISO/IEC 9899:1990):
  • 4.9.7.9 The putchar function

See also