Function esp_idf_svc::sys::esp_vfs_select

pub unsafe extern "C" fn esp_vfs_select(
    nfds: i32,
    readfds: *mut fd_set,
    writefds: *mut fd_set,
    errorfds: *mut fd_set,
    timeout: *mut timeval,
) -> i32

@brief Synchronous I/O multiplexing which implements the functionality of POSIX select() for VFS @param nfds Specifies the range of descriptors which should be checked. The first nfds descriptors will be checked in each set. @param readfds If not NULL, then points to a descriptor set that on input specifies which descriptors should be checked for being ready to read, and on output indicates which descriptors are ready to read. @param writefds If not NULL, then points to a descriptor set that on input specifies which descriptors should be checked for being ready to write, and on output indicates which descriptors are ready to write. @param errorfds If not NULL, then points to a descriptor set that on input specifies which descriptors should be checked for error conditions, and on output indicates which descriptors have error conditions. @param timeout If not NULL, then points to timeval structure which specifies the time period after which the functions should time-out and return. If it is NULL, then the function will not time-out. Note that the timeout period is rounded up to the system tick and incremented by one.

@return The number of descriptors set in the descriptor sets, or -1 when an error (specified by errno) have occurred.