nuttx/include/sys/select.h
Xiang Xiao fa3e0faffc fs: Map FD_SETSIZE to OPEN_MAX instead hardcoding 256
and change the default value of LIBC_OPEN_MAX to 256.
Here has more discussion:
https://www.mail-archive.com/dev@nuttx.apache.org/msg09095.html

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
2023-02-19 19:17:20 +02:00

121 lines
3.6 KiB
C

/****************************************************************************
* include/sys/select.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
#ifndef __INCLUDE_SYS_SELECT_H
#define __INCLUDE_SYS_SELECT_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <limits.h>
#include <stdint.h>
#include <signal.h>
#include <sys/time.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Get the total number of descriptors that we will have to support */
#define FD_SETSIZE OPEN_MAX
/* We will use a 32-bit bitsets to represent the set of descriptors. How
* many uint32_t's do we need to span all descriptors?
*/
#if FD_SETSIZE <= 32
# define __SELECT_NUINT32 1
#elif FD_SETSIZE <= 64
# define __SELECT_NUINT32 2
#elif FD_SETSIZE <= 96
# define __SELECT_NUINT32 3
#elif FD_SETSIZE <= 128
# define __SELECT_NUINT32 4
#elif FD_SETSIZE <= 160
# define __SELECT_NUINT32 5
#elif FD_SETSIZE <= 192
# define __SELECT_NUINT32 6
#elif FD_SETSIZE <= 224
# define __SELECT_NUINT32 7
#elif FD_SETSIZE <= 256
# define __SELECT_NUINT32 8
#else
# warning "Larger fd_set needed"
#endif
/* These macros map a file descriptor to an index and bit number */
#define _FD_NDX(fd) ((fd) >> 5)
#define _FD_BIT(fd) ((fd) & 0x1f)
/* Standard helper macros */
#define FD_CLR(fd,set) \
((((fd_set*)(set))->arr)[_FD_NDX(fd)] &= ~(UINT32_C(1)<< _FD_BIT(fd)))
#define FD_SET(fd,set) \
((((fd_set*)(set))->arr)[_FD_NDX(fd)] |= (UINT32_C(1) << _FD_BIT(fd)))
#define FD_ISSET(fd,set) \
(((((fd_set*)(set))->arr)[_FD_NDX(fd)] & (UINT32_C(1) << _FD_BIT(fd))) != 0)
#define FD_ZERO(set) \
memset((set), 0, sizeof(fd_set))
/****************************************************************************
* Type Definitions
****************************************************************************/
struct fd_set_s
{
uint32_t arr[__SELECT_NUINT32];
};
typedef struct fd_set_s fd_set;
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
struct timeval;
int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds,
FAR fd_set *exceptfds, FAR struct timeval *timeout);
int pselect(int nfds, FAR fd_set *readfds, FAR fd_set *writefds,
FAR fd_set *exceptfds, FAR const struct timespec *timeout,
FAR const sigset_t *sigmask);
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __INCLUDE_SYS_SELECT_H */