A return value of – 1 indicates an error, and errno is set to one of the following values:
E2BIG
Argument list (which is system dependent) is too big.
ENOENT
Command interpreter cannot be found.
ENOEXEC
Command-interpreter file has invalid format and is not executable.
ENOMEM
Not enough memory is available to execute command; or available memory has been corrupted; or invalid block exists, indicating that process making call was not allocated properly.
Verifica il valore di errno per individuare l'errore.