June 4, 1993 USLEEP 3

### NAME

usleep - suspend execution for interval of microseconds

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` usleep(```useconds_t microseconds`)

### DESCRIPTION

The usleep(``) function suspends execution of the calling process until either the number of microseconds specified by ```microseconds` have elapsed or a signal is delivered to the calling process and its action is to invoke a signal catching function or to terminate the process. The suspension time may be longer than requested due to the scheduling of other activity by the system.

The ```microseconds` argument must be less than 1,000,000. If the value of ```microseconds` is 0, then the call has no effect.

### RETURN VALUES

On successful completion, usleep(``) returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

### ERRORS

The usleep(``) function may fail if:

[```EINVAL`]
  The ```microseconds` interval specified 1,000,000 or more microseconds.

### SEE ALSO

nanosleep(2), sleep(3)

### STANDARDS

The usleep(``) function conforms to X/Open Portability Guide Issue 4, Version 2 (``XPG4.2'') .

### HISTORY

The usleep(``) function appeared in 4.3BSD.