在Ubuntu中编译含有JSON的文件出现报错

在ubuntu中进行JSON相关学习的时候，我发现了一些小问题，决定与大家进行分享，减少踩坑时候出现不必要的时间耗费

截取部分含有JSON部分的代码进行展示
char *str = "{  \"title\":\"JSON Example\",  \"author\": {  \"name\":\"John Doe\",  \"age\": 35,  \"isVerified\":true  },  \"tags\":[\"json\", \"syntax\", \"example\"],  \"rating\": 4.5,  \"isPublished\":false,  \"comments\": null  }";
按照JSON格式，在引号前边都需要加上 \ 反斜杠

其余部分的代码与本次的错误分享无关，暂不截图

打开终端执行 gcc -o json_test json_test.c 命令对本测试代码进行编译

以下为在编译过程中出现的报错，

可以发现报错的部分非常的多，而且都明显的指向 \ 反斜杠这一方面的错误

以下为全部的报错

json_test.c: In function ‘main’:
json_test.c:6:14: error: stray ‘\’ in programchar *str = \"^
json_test.c:6:15: warning: missing terminating " characterchar *str = \"^
json_test.c:6:15: error: missing terminating " character
json_test.c:8:5: error: stray ‘\’ in program\"title\":\"JSON Example\",^
json_test.c:8:6: warning: missing terminating " character\"title\":\"JSON Example\",^
json_test.c:8:6: error: missing terminating " character\"title\":\"JSON Example\",^~~~~~~~~~~~~~~~~~~~~~~~~~  
json_test.c:9:5: error: stray ‘\’ in program\"author\": {^
json_test.c:9:6: warning: missing terminating " character\"author\": {^
json_test.c:9:6: error: missing terminating " character\"author\": {^~~~~~~~~~~~  
json_test.c:10:5: error: stray ‘\’ in program\"name\":\"John Doe\",^
json_test.c:10:6: warning: missing terminating " character\"name\":\"John Doe\",^
json_test.c:10:6: error: missing terminating " character\"name\":\"John Doe\",^~~~~~~~~~~~~~~~~~~~~  
json_test.c:11:5: error: stray ‘\’ in program\"age\": 35,^
json_test.c:11:6: warning: missing terminating " character\"age\": 35,^
json_test.c:11:6: error: missing terminating " character\"age\": 35,^~~~~~~~~~~  
json_test.c:12:5: error: stray ‘\’ in program\"isVerified\":true^
json_test.c:12:6: warning: missing terminating " character\"isVerified\":true^
json_test.c:12:6: error: missing terminating " character\"isVerified\":true^~~~~~~~~~~~~~~~~~  
json_test.c:7:5: error: empty scalar initializer{^
json_test.c:7:5: note: (near initialization for ‘str’)
json_test.c:14:5: error: stray ‘\’ in program\"tags\":[\"json\", \"syntax\", \"example\"],^
json_test.c:14:6: warning: missing terminating " character\"tags\":[\"json\", \"syntax\", \"example\"],^
json_test.c:14:6: error: missing terminating " character\"tags\":[\"json\", \"syntax\", \"example\"],^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
json_test.c:15:5: error: stray ‘\’ in program\"rating\": 4.5,^
json_test.c:15:6: warning: missing terminating " character\"rating\": 4.5,^
json_test.c:15:6: error: missing terminating " character\"rating\": 4.5,^~~~~~~~~~~~~~~  
json_test.c:16:5: error: stray ‘\’ in program\"isPublished\":false,^
json_test.c:16:6: warning: missing terminating " character\"isPublished\":false,^
json_test.c:16:6: error: missing terminating " character\"isPublished\":false,^~~~~~~~~~~~~~~~~~~~~  
json_test.c:17:5: error: stray ‘\’ in program\"comments\": null^
json_test.c:17:6: warning: missing terminating " character\"comments\": null^
json_test.c:17:6: error: missing terminating " character\"comments\": null^~~~~~~~~~~~~~~~~  
json_test.c:18:5: error: expected identifier or ‘(’ before ‘}’ token}\";^
json_test.c:18:6: error: stray ‘\’ in program}\";^
json_test.c:18:7: warning: missing terminating " character}\";^
json_test.c:18:7: error: missing terminating " character}\";^~

对于这个问题的解决其实不难，只需要在每一行的后边加上连词符号 \ 即可，将多行拼成1行

代码做出修改后如下：

char *str = "\{  \\"title\":\"JSON Example\",\ \"author\": {  \\"name\":\"John Doe\",\\"age\": 35,\\"isVerified\":true\}, \\"tags\":[\"json\", \"syntax\", \"example\"],\ \"rating\": 4.5,\\"isPublished\":false,\\"comments\": null\}";

再次对其进行编译，之前的报错基本消失

但是，我们发现了另外一个警告错误
json_test.c: In function ‘main’:
json_test.c:8:32: warning: backslash and newline separated by space\"title\":\"JSON Example\",\json_test.c:14:51: warning: backslash and newline separated by space\"tags\":[\"json\", \"syntax\", \"example\"], \/tmp/ccFimHV4.o: In function `main':
json_test.c:(.text+0x22): undefined reference to `cJSON_Parse'
json_test.c:(.text+0x39): undefined reference to `cJSON_GetObjectItem'
collect2: error: ld returned 1 exit status
同时回到text editor代码中，发现代码中反斜杠居然会出现两种颜色

这个现象很有意思，一开始并没有注意这是为什么，后边结合警告

在这几个颜色不同的反斜杠之间瞎点，发现一个小问题

这些不同于大众的颜色的反斜杠，后边带有空格，其他的没有

尝试着将后边的空格去掉之后，再次进行编译，前边的警告错误荡然无存