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在Ubuntu中编译含有JSON的文件出现报错

article 2024/9/23 5:32:59

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 program
  char *str = \"
              ^
json_test.c:6:15: warning: missing terminating " character
  char *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