From 6fe7e5db355c66116791284819c9fedcf73029a8 Mon Sep 17 00:00:00 2001
From: guowenxue <guowenxue@gmail.com>
Date: Sun, 14 Oct 2018 17:54:49 +0800
Subject: [PATCH] Add APUE folder in program and add File IO sample code
---
program/apue/1.File_IO/makefile | 11 +++
program/apue/1.File_IO/ds18b20.c | 119 +++++++++++++++++++++++++++++++++++++++
2 files changed, 130 insertions(+), 0 deletions(-)
diff --git a/program/apue/1.File_IO/ds18b20.c b/program/apue/1.File_IO/ds18b20.c
new file mode 100644
index 0000000..d170de1
--- /dev/null
+++ b/program/apue/1.File_IO/ds18b20.c
@@ -0,0 +1,119 @@
+/*********************************************************************************
+ * Copyright: (C) 2018 LingYun IoT System Studio
+ * All rights reserved.
+ *
+ * Filename: ds18b20.c
+ * Description: This file is temperature sensor DS18B20 code
+ *
+ * Version: 1.0.0(2018/10/14)
+ * Author: Guo Wenxue <guowenxue@gmail.com>
+ * ChangeLog: 1, Release initial version on "2018/10/14 12:13:26"
+ *
+ ********************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+
+int ds18b20_get_temperature(float *temp);
+
+int main(int argc, char *argv[])
+{
+ float temp;
+
+ if( ds18b20_get_temperature(&temp) < 0 )
+ {
+ printf("ERROR: ds18b20 get temprature failure\n");
+ return 1;
+ }
+
+ printf("DS19B20 get temperature: %f ℃\n", temp);
+ return 0;
+}
+
+
+/* File Content:
+ pi@raspberrypi:~/guowenxue $ cat /sys/bus/w1/devices/28-041731f7c0ff/w1_slave
+ 3a 01 4b 46 7f ff 0c 10 a5 : crc=a5 YES
+ 3a 01 4b 46 7f ff 0c 10 a5 t=19625
+ */
+
+int ds18b20_get_temperature(float *temp)
+{
+ char w1_path[50] = "/sys/bus/w1/devices/";
+ char chip[20];
+ char buf[128];
+ DIR *dirp;
+ struct dirent *direntp;
+ int fd =-1;
+ char *ptr;
+ float value;
+ int found = 0;
+
+ if( !temp )
+ {
+ return -1;
+ }
+
+ /*+-------------------------------------------------------------------+
+ *| open dierectory /sys/bus/w1/devices to get chipset Serial Number |
+ *+-------------------------------------------------------------------+*/
+ if((dirp = opendir(w1_path)) == NULL)
+ {
+ printf("opendir error: %s\n", strerror(errno));
+ return -2;
+ }
+
+ while((direntp = readdir(dirp)) != NULL)
+ {
+ if(strstr(direntp->d_name,"28-"))
+ {
+ /* find and get the chipset SN filename */
+ strcpy(chip,direntp->d_name);
+ found = 1;
+ }
+ }
+ closedir(dirp);
+
+ if( !found )
+ {
+ printf("Can not find ds18b20 in %s\n", w1_path);
+ return -3;
+ }
+
+ /* get DS18B20 sample file full path: /sys/bus/w1/devices/28-xxxx/w1_slave */
+ strncat(w1_path, chip, sizeof(w1_path)-strlen(w1_path));
+ strncat(w1_path, "/w1_slave", sizeof(w1_path)-strlen(w1_path));
+
+ /* open file /sys/bus/w1/devices/28-xxxx/w1_slave to get temperature */
+ if( (fd=open(w1_path, O_RDONLY)) < 0 )
+ {
+ printf("open %s error: %s\n", w1_path, strerror(errno));
+ return -4;
+ }
+
+ if(read(fd, buf, sizeof(buf)) < 0)
+ {
+ printf("read %s error: %s\n", w1_path, strerror(errno));
+ return -5;
+ }
+
+ ptr = strstr(buf, "t=");
+ if( !ptr )
+ {
+ printf("ERROR: Can not get temperature\n");
+ return -6;
+ }
+
+ ptr+=2;
+
+ /* convert string value to float value */
+ *temp = atof(ptr)/1000;
+
+ return 0;
+}
diff --git a/program/apue/1.File_IO/makefile b/program/apue/1.File_IO/makefile
new file mode 100644
index 0000000..cbae8a0
--- /dev/null
+++ b/program/apue/1.File_IO/makefile
@@ -0,0 +1,11 @@
+INST_PATH=/usr/bin
+BIN_NAME=ds18b20
+
+all:
+ gcc ${BIN_NAME}.c -o ${BIN_NAME}
+
+clean:
+ rm -f ${BIN_NAME}
+
+install:
+ @cp ${BIN_NAME} ${INST_PATH}
--
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