GCC出现warning: integer constant is too large for 'long' type"

The warning message can be safely ignored, as mb-gcc is not doing anything wrong; the 64-bit computing is in fact correct.

This warning occurs because gcc is strict in syntax and requires LL on the end of such constants. This warning message disappears if the integer is appended with LL.

long long int test = 0x0008888000000000LL;

http://mazaoliang.blog.163.com/blog/static/138455093201151603823383/


root@ubuntu:/home/t101/paho.mqtt.c-master# make mkdir -p build/output/samples mkdir -p build/output/test echo OSTYPE is Linux OSTYPE is Linux sed -e "s/@CLIENT_VERSION@/1.3.0/g" -e "s/@BUILD_TIMESTAMP@/Thu Jun 19 06:23:05 PDT 2025/g" src/VersionInfo.h.in > build/VersionInfo.h arm-linux-gcc -g -fPIC -I/home/t101/sysdir/ssl/include/ -Os -Wall -Ibuild -o build/output/libpaho-mqtt3c.so.1.0 src/Heap.c src/Socket.c src/MQTTProtocolClient.c src/MQTTProtocolOut.c src/SHA1.c src/StackTrace.c src/MQTTProperties.c src/MQTTPersistenceDefault.c src/MQTTPacketOut.c src/WebSocket.c src/Clients.c src/OsWrapper.c src/MQTTPacket.c src/Base64.c src/MQTTClient.c src/Log.c src/Thread.c src/LinkedList.c src/MQTTReasonCodes.c src/MQTTPersistence.c src/utf-8.c src/SocketBuffer.c src/Tree.c src/Messages.c -L/home/t101/sysdir/ssl/lib -shared -Wl,-init,MQTTClient_init -lpthread -Wl,-soname,libpaho-mqtt3c.so.1 src/SHA1.c: In function `SHA1_ProcessBlock': src/SHA1.c:112: warning: implicit declaration of function `__builtin_bswap32' src/WebSocket.c: In function `WebSocket_buildFrame': src/WebSocket.c:225: warning: implicit declaration of function `__builtin_bswap16' src/WebSocket.c:230: warning: integer constant is too large for "long" type src/WebSocket.c:230: warning: comparison is always true due to limited range of data type src/WebSocket.c:232: warning: implicit declaration of function `__builtin_bswap64' src/WebSocket.c: In function `WebSocket_calculateFrameHeaderSize': src/WebSocket.c:297: warning: integer constant is too large for "long" type src/WebSocket.c:297: warning: comparison is always true due to limited range of data type ln -s libpaho-mqtt3c.so.1.0 build/output/libpaho-mqtt3c.so.1 ln -s libpaho-mqtt3c.so.1 build/output/libpaho-mqtt3c.so arm-linux-gcc -g -fPIC -I/home/t101/sysdir/ssl/include/ -Os -Wall -Ibuild -o build/output/libpaho-mqtt3cs.so.1.0 src/Heap.c src/Socket.c src/SSLSocket.c src/MQTTProtocolClient.c src/MQTTProtocolOut.c src/SHA1.c src/StackTrace.c src/MQTTProperties.c src/MQTTPersistenceDefault.c src/MQTTPacketOut.c src/WebSocket.c src/Clients.c src/OsWrapper.c src/MQTTPacket.c src/Base64.c src/MQTTClient.c src/Log.c src/Thread.c src/LinkedList.c src/MQTTReasonCodes.c src/MQTTPersistence.c src/utf-8.c src/SocketBuffer.c src/Tree.c src/Messages.c -DOPENSSL -L/home/t101/sysdir/ssl/lib -shared -Wl,--start-group -lpthread -ldl -lssl -lcrypto -Wl,--end-group -Wl,-init,MQTTClient_init -Wl,-soname,libpaho-mqtt3cs.so.1 -Wl,-no-whole-archive src/SSLSocket.c: In function `SSLSocket_createContext': src/SSLSocket.c:537: warning: `TLSv1_client_method' is deprecated (declared at /home/t101/sysdir/ssl/include/openssl/ssl.h:1866) src/SSLSocket.c:542: warning: `TLSv1_1_client_method' is deprecated (declared at /home/t101/sysdir/ssl/include/openssl/ssl.h:1872) src/SSLSocket.c:547: warning: `TLSv1_2_client_method' is deprecated (declared at /home/t101/sysdir/ssl/include/openssl/ssl.h:1878) src/SSLSocket.c: In function `SSLSocket_initialize': src/SSLSocket.c:476: warning: statement with no effect src/WebSocket.c: In function `WebSocket_buildFrame': src/WebSocket.c:225: warning: implicit declaration of function `__builtin_bswap16' src/WebSocket.c:230: warning: integer constant is too large for "long" type src/WebSocket.c:230: warning: comparison is always true due to limited range of data type src/WebSocket.c:232: warning: implicit declaration of function `__builtin_bswap64' src/WebSocket.c: In function `WebSocket_calculateFrameHeaderSize': src/WebSocket.c:297: warning: integer constant is too large for "long" type src/WebSocket.c:297: warning: comparison is always true due to limited range of data type ln -s libpaho-mqtt3cs.so.1.0 build/output/libpaho-mqtt3cs.so.1 ln -s libpaho-mqtt3cs.so.1 build/output/libpaho-mqtt3cs.so arm-linux-gcc -g -fPIC -I/home/t101/sysdir/ssl/include/ -Os -Wall -Ibuild -o build/output/libpaho-mqtt3a.so.1.0 src/Heap.c src/Socket.c src/MQTTProtocolClient.c src/MQTTProtocolOut.c src/MQTTAsync.c src/SHA1.c src/StackTrace.c src/MQTTProperties.c src/MQTTPersistenceDefault.c src/MQTTPacketOut.c src/WebSocket.c src/Clients.c src/OsWrapper.c src/MQTTPacket.c src/Base64.c src/Log.c src/Thread.c src/LinkedList.c src/MQTTReasonCodes.c src/MQTTPersistence.c src/utf-8.c src/SocketBuffer.c src/Tree.c src/Messages.c -L/home/t101/sysdir/ssl/lib -shared -Wl,-init,MQTTAsync_init -lpthread -Wl,-soname,libpaho-mqtt3a.so.1 src/SHA1.c: In function `SHA1_ProcessBlock': src/SHA1.c:112: warning: implicit declaration of function `__builtin_bswap32' src/WebSocket.c: In function `WebSocket_buildFrame': src/WebSocket.c:225: warning: implicit declaration of function `__builtin_bswap16' src/WebSocket.c:230: warning: integer constant is too large for "long" type src/WebSocket.c:230: warning: comparison is always true due to limited range of data type src/WebSocket.c:232: warning: implicit declaration of function `__builtin_bswap64' src/WebSocket.c: In function `WebSocket_calculateFrameHeaderSize': src/WebSocket.c:297: warning: integer constant is too large for "long" type src/WebSocket.c:297: warning: comparison is always true due to limited range of data type ln -s libpaho-mqtt3a.so.1.0 build/output/libpaho-mqtt3a.so.1 ln -s libpaho-mqtt3a.so.1 build/output/libpaho-mqtt3a.so arm-linux-gcc -g -fPIC -I/home/t101/sysdir/ssl/include/ -Os -Wall -Ibuild -o build/output/libpaho-mqtt3as.so.1.0 src/Heap.c src/Socket.c src/SSLSocket.c src/MQTTProtocolClient.c src/MQTTProtocolOut.c src/MQTTAsync.c src/SHA1.c src/StackTrace.c src/MQTTProperties.c src/MQTTPersistenceDefault.c src/MQTTPacketOut.c src/WebSocket.c src/Clients.c src/OsWrapper.c src/MQTTPacket.c src/Base64.c src/Log.c src/Thread.c src/LinkedList.c src/MQTTReasonCodes.c src/MQTTPersistence.c src/utf-8.c src/SocketBuffer.c src/Tree.c src/Messages.c -DOPENSSL -L/home/t101/sysdir/ssl/lib -shared -Wl,--start-group -lpthread -ldl -lssl -lcrypto -Wl,--end-group -Wl,-init,MQTTAsync_init -Wl,-soname,libpaho-mqtt3as.so.1 -Wl,-no-whole-archive src/SSLSocket.c: In function `SSLSocket_createContext': src/SSLSocket.c:537: warning: `TLSv1_client_method' is deprecated (declared at /home/t101/sysdir/ssl/include/openssl/ssl.h:1866) src/SSLSocket.c:542: warning: `TLSv1_1_client_method' is deprecated (declared at /home/t101/sysdir/ssl/include/openssl/ssl.h:1872) src/SSLSocket.c:547: warning: `TLSv1_2_client_method' is deprecated (declared at /home/t101/sysdir/ssl/include/openssl/ssl.h:1878) src/SSLSocket.c: In function `SSLSocket_initialize': src/SSLSocket.c:476: warning: statement with no effect src/WebSocket.c: In function `WebSocket_buildFrame': src/WebSocket.c:225: warning: implicit declaration of function `__builtin_bswap16' src/WebSocket.c:230: warning: integer constant is too large for "long" type src/WebSocket.c:230: warning: comparison is always true due to limited range of data type src/WebSocket.c:232: warning: implicit declaration of function `__builtin_bswap64' src/WebSocket.c: In function `WebSocket_calculateFrameHeaderSize': src/WebSocket.c:297: warning: integer constant is too large for "long" type src/WebSocket.c:297: warning: comparison is always true due to limited range of data type ln -s libpaho-mqtt3as.so.1.0 build/output/libpaho-mqtt3as.so.1 ln -s libpaho-mqtt3as.so.1 build/output/libpaho-mqtt3as.so arm-linux-gcc -L/home/t101/sysdir/ssl/lib -I src -lpthread -L build/output -o build/output/paho_c_version -lpaho-mqtt3a src/MQTTVersion.c -ldl build/output/libpaho-mqtt3a.so: undefined reference to `clock_gettime' build/output/libpaho-mqtt3a.so: undefined reference to `__builtin_bswap16' build/output/libpaho-mqtt3a.so: undefined reference to `__builtin_bswap32' build/output/libpaho-mqtt3a.so: undefined reference to `__builtin_bswap64' collect2: ld returned 1 exit status Makefile:274: recipe for target 'build/output/paho_c_version' failed make: *** [build/output/paho_c_version] Error 1
最新发布
06-20
<think>嗯,用户遇到了一个编译错误,说是“integer constant too large for 'long' type”。我需要帮他们解决这个问题。首先,我得回忆一下C/C++中整数常量的类型推断规则。 在C和C++中,整型常量的类型会根据数值的大小自动推断。比如,如果数字超过了long能表示的范围,编译器就会报错。这时候,用户可能需要使用更大的类型,比如long long或者unsigned long long。不过,用户可能不知道如何明确指定常量的类型,所以需要指导他们添加后缀,比如LL或ULL。 另外,不同的编译器可能有不同的行为,尤其是在32位和64位系统上,long的大小可能不同。比如,在32位系统中,long通常是4字节,而64位系统可能是8字节。这也可能导致用户在不同环境下遇到不同的情况。这时候,建议用户检查编译器的位数,以及使用sizeof来确认类型的大小。 还有,用户可能没有意识到使用无符号类型可以扩展正数的范围。例如,unsigned long long的范围比signed的大,所以对于非常大的正数,使用ULL后缀会更合适。需要提醒用户注意这一点。 此外,如果用户需要处理特别大的整数,可能需要使用高精度库,如GMP,或者将数字写成字符串处理。不过这可能超出了当前问题的范围,但可以作为扩展建议提出。 最后,确保用户正确使用了后缀,比如在数字后面加上LL或ULL,而不仅仅是L或U。同时,提醒他们在跨平台时要注意类型大小的差异,避免再次出现类似的问题。</think>### 关于"integer constant too large for 'long' type"的解决方案 #### 1. 问题原因分析 在C/C++中,当整型字面量超过`long`类型最大值时会出现该错误。`long`类型在不同平台下的范围不同: - 32位系统:通常4字节($-2^{31}$到$2^{31}-1$) - 64位系统:通常8字节($-2^{63}$到$2^{63}-1$) #### 2. 解决方案步骤 ① **添加类型后缀**(推荐) ```c long long big_num = 9223372036854775808LL; // 添加LL后缀表示long long类型 unsigned long long huge_num = 18446744073709551615ULL; // ULL表示unsigned long long ``` ② **检查编译器位数** ```bash gcc -dM -E - < /dev/null | grep -i 64 # 检查是否64位编译器 ``` ③ **验证类型尺寸** ```c printf("long size: %zu\n", sizeof(long)); // 输出long类型字节数 ``` ④ **使用标准头文件** ```c #include <stdint.h> int64_t safe_num = INT64_MAX; // 精确指定位数 ``` #### 3. 扩展建议 对于超过$2^{128}$的数值,建议: - 使用高精度库(如GMP) - 将数值转换为字符串处理 - 采用科学计数法近似存储 #### 4. 验证示例 ```c #include <stdio.h> #include <stdint.h> int main() { // 正确写法 unsigned long long valid = 18446744073709551615ULL; // 错误写法(触发编译错误) // long invalid = 9223372036854775808; printf("%llu\n", valid); return 0; } ```
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