$ arm-linux-gnueabihf-g++ -std=c++11 -Wall -I ../inc -c i2c-core.cpp
i2c-core.cpp: In function 'int i2c_read(int, short unsigned int, unsigned char*, int)':
i2c-core.cpp:20:13: warning: narrowing conversion of '(((int)reg) >> 8)' from 'int' to 'unsigned char' inside { } [-Wnarrowing]
reg >> 8,
^
i2c-core.cpp:21:13: warning: narrowing conversion of '(((int)reg) & 255)' from 'int' to 'unsigned char' inside { } [-Wnarrowing]
reg & 0xff,
^
--- a/project/src/i2c-core.c
+++ b/project/src/i2c-core.c
@@ -17,8 +17,8 @@ int i2c_read(int fd, unsigned short reg, unsigned char *rbuf, int len){
i2c_data.nmsgs = 2;
i2c_data.msgs = msgs;
unsigned char tbuf[] = {
- reg >> 8,
- reg & 0xff,
+ static_cast<unsigned char>(reg >> 8),
+ static_cast<unsigned char>(reg & 0xff),
};
msgs[0].flags = 0; //写标志
msgs[0].addr = DEVICE_I2C_ADDR; //i2c地址
