examples/posix_stdio: New example dedicated to posix stdio library.

This example will help newcomers to port software from Linux to NuttX
in a POSIX compliant fashion using stdio library. It shows how to work with
open(), close() and write() functions over /dev/console.

Signed-off-by: Vinicius May <vmay.sweden@gmail.com>
This commit is contained in:
vrmay23 2025-04-27 18:52:14 +02:00 committed by Xiang Xiao
parent 30ef8ff845
commit 77b2e8dfee
5 changed files with 212 additions and 0 deletions

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# ##############################################################################
# apps/examples/posix_stdio/CMakeLists.txt
#
# SPDX-License-Identifier: Apache-2.0
#
# 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.
#
# ##############################################################################
if(CONFIG_EXAMPLES_POSIX_STDIO)
nuttx_add_application(
NAME
${CONFIG_EXAMPLES_POSIX_STDIO_PROGNAME}
PRIORITY
${CONFIG_EXAMPLES_POSIX_STDIO_PRIORITY}
STACKSIZE
${CONFIG_EXAMPLES_POSIX_STDIO_STACKSIZE}
MODULE
${CONFIG_EXAMPLES_POSIX_STDIO}
SRCS
posix_stdio.c)
endif()

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#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#
config EXAMPLES_POSIX_STDIO
bool "Posix stdio example"
default n
---help---
Enable POSIX stdio example that shows how to use open(), write() and close() via /dev/console.
config EXAMPLES_POSIX_STDIO_PROGNAME
string "Program name"
default "posix_stdio"
depends on EXAMPLES_POSIX_STDIO
config EXAMPLES_POSIX_STDIO_PRIORITY
int "POSIX_STDIO test priority"
default 100
depends on EXAMPLES_POSIX_STDIO

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############################################################################
# apps/examples/posix_stdio/Make.defs
#
# SPDX-License-Identifier: Apache-2.0
#
# 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.
#
############################################################################
ifneq ($(CONFIG_EXAMPLES_POSIX_STDIO),)
CONFIGURED_APPS += $(APPDIR)/examples/posix_stdio
endif

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############################################################################
# apps/examples/posix_stdio/Makefile
#
# SPDX-License-Identifier: Apache-2.0
#
# 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.
#
############################################################################
include $(APPDIR)/Make.defs
PROGNAME = $(CONFIG_EXAMPLES_POSIX_STDIO_PROGNAME)
PRIORITY = $(CONFIG_EXAMPLES_POSIX_STDIO_PRIORITY)
STACKSIZE = $(CONFIG_EXAMPLES_POSIX_STDIO_STACKSIZE)
MODULE = $(CONFIG_EXAMPLES_POSIX_STDIO)
MAINSRC = posix_stdio.c
include $(APPDIR)/Application.mk

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/****************************************************************************
* apps/examples/posix_stdio/posix_stdio.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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.
*
****************************************************************************/
/****************************************************************************
* This is a single POSIX example that works for both Nuttx and Linux distros
* (with minimal changes). By this example its possible to learn how to use
* posix style and also works with onpen(), close() and write() functions.
*
* For linux, need to change the headers and the output device
* A) Headers:
* #include <fcntl.h>
* #include <unistd.h>
* #include <stdio.h>
* #include <string.h>
*
* B) output:
* /dev/tty
*
* To compile it on Linux, you can simple use gcc:
* gcc posix_stdio.c -o posix_stdio
*
* To run, just send the following command: ./posix_stdio
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <stdio.h>
/****************************************************************************
* Pre-processor Definitions
* *************************************************************************/
/* define how many times the message will be printed in the console */
#ifndef PRINT_N_TIMES
# define PRINT_N_TIMES 10
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
static void print_message(int fd)
{
const char *message = "Hello, NuttX users, welcome!!!\n";
write(fd, message, strlen(message));
}
/****************************************************************************
* hello_nuttx_main
****************************************************************************/
int main(int argc, char *argv[])
{
int counter;
int fd = open("/dev/console", O_WRONLY);
if (fd < 0)
{
fprintf(stderr, "Failed to open console\n");
return 1;
}
for (counter = 0; counter < PRINT_N_TIMES; counter++)
{
print_message(fd);
}
close(fd);
return 0;
}