fgetc() — Read a character

Standards

Standards / Extensions	C or C++	Dependencies
ISO C POSIX.1 XPG4 XPG4.2 C99 Single UNIX Specification, Version 3 Language Environment	both

Format

#include <stdio.h>

int fgetc(FILE *stream);

#define _OPEN_SYS_UNLOCKED_EXT 1
#include <stdio.h>

int fgetc_unlocked(FILE *stream);

General description

Reads a single-byte unsigned character from the input stream pointed to by stream at the current position, and increases the associated file pointer so that it points to the next character.

The fgetc() function is not supported for files opened with type=record or type=blocked.

fgetc() has the same restriction as any read operation for a read immediately following a write or a write immediately following a read. Between a write and a subsequent read, there must be an intervening flush or reposition. Between a read and a subsequent write, there must also be an intervening flush or reposition unless an EOF has been reached.

fgetc_unlocked() is functionally equivalent to fgetc() with the exception that it is not thread-safe. This function can safely be used in a multithreaded application if and only if it is called while the invoking thread owns the (FILE*) object, as is the case after a successful call to either the flockfile() or ftrylockfile() function.

Returned value

If successful, fgetc() returns the character read as an integer.

If unsuccessful, fgetc() returns EOF to indicate an error or an EOF condition. Use feof() or ferror() to determine whether the EOF value indicates an error or the end of the file.

Note: EOF is only reached when an attempt is made to read “past” the last byte of data. Reading up to and including the last byte of data does not turn on the EOF indicator.

Example

CELEBF16

⁄* CELEBF16                                      

   This example gathers a line of input from a stream.                          
   It tests to see if the file can be opened.                                   
   If the file cannot be opened &perror. is called.                             
                                                                                
 *⁄                                                                             
#include <stdio.h>                                                              
#define  MAX_LEN  80                                                            
                                                                                
int main(void)                                                                  
{                                                                               
   FILE *stream;                                                                
   char buffer[MAX_LEN + 1];                                                    
   int i, ch;                                                                   
                                                                                
   if ((stream = fopen("myfile.dat","r")) != NULL) {                            
     for (i = 0; (i < (sizeof(buffer)-1) &&                                     
           ((ch = fgetc(stream)) != EOF) && (ch != '\n')); i++)                 
        printf("character is %d\n",ch);                                         
        buffer[i] = ch;                                                         
                                                                                
     buffer[i] = '\0';                                                          
                                                                                
     if (fclose(stream))                                                        
        perror("fclose error");                                                 
   }                                                                            
   else                                                                         
     perror("fopen error");                                                     
}