How to use read() to read data until the end of the file?

Question

I\'m trying to read binary data in a C program with read() but EOF test doesn\'t work. Instead it keeps running forever reading the last bit of the file.

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Answer 1

POSIX rasys return == 0 for end of file

http://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html

If no process has the pipe open for writing, read() shall return 0 to indicate end-of-file.

This confirms Jerry's answer.

EOF is returned by some ANSI functions, e.g. man getc says:

fgetc(), getc() and getchar() return the character read as an unsigned char cast to an int or EOF on end of file or error.

ungetc() returns c on success, or EOF on error.

so you still can't use it to distinguish error and end of file in that case, feof is needed.

See also: How to use EOF to run through a text file in C?