centos7 pip3 install mysqlclient error: command '/usr/bin/gcc' failed with exit code 1

[daifengqi]

Python version is 3.9.0

MySQL is mysql80-community-release-el7-3.noarch.rpm

ERROR: Command errored out with exit status 1:
     command: /home/cesc/envme/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-7imlhj3_/mysqlclient_4abebc3dfb814f09b6c8b217e744025e/setup.py'"'"'; __file__='"'"'/tmp/pip-install-7imlhj3_/mysqlclient_4abebc3dfb814f09b6c8b217e744025e/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-usi8p1fw/install-record.txt --single-version-externally-managed --compile --install-headers /home/cesc/envme/include/site/python3.9/mysqlclient
         cwd: /tmp/pip-install-7imlhj3_/mysqlclient_4abebc3dfb814f09b6c8b217e744025e/
    Complete output (31 lines):
    running install
    running build
    running build_py
    creating build
    creating build/lib.linux-x86_64-3.9
    creating build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/__init__.py -> build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/_exceptions.py -> build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/connections.py -> build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/converters.py -> build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/cursors.py -> build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/release.py -> build/lib.linux-x86_64-3.9/MySQLdb
    copying MySQLdb/times.py -> build/lib.linux-x86_64-3.9/MySQLdb
    creating build/lib.linux-x86_64-3.9/MySQLdb/constants
    copying MySQLdb/constants/__init__.py -> build/lib.linux-x86_64-3.9/MySQLdb/constants
    copying MySQLdb/constants/CLIENT.py -> build/lib.linux-x86_64-3.9/MySQLdb/constants
    copying MySQLdb/constants/CR.py -> build/lib.linux-x86_64-3.9/MySQLdb/constants
    copying MySQLdb/constants/ER.py -> build/lib.linux-x86_64-3.9/MySQLdb/constants
    copying MySQLdb/constants/FIELD_TYPE.py -> build/lib.linux-x86_64-3.9/MySQLdb/constants
    copying MySQLdb/constants/FLAG.py -> build/lib.linux-x86_64-3.9/MySQLdb/constants
    running build_ext
    building 'MySQLdb._mysql' extension
    creating build/temp.linux-x86_64-3.9
    creating build/temp.linux-x86_64-3.9/MySQLdb
    gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -Dversion_info=(2,0,2,'final',0) -D__version__=2.0.2 -I/usr/include/mysql -I/home/cesc/envme/include -I/usr/local/include/python3.9 -c MySQLdb/_mysql.c -o build/temp.linux-x86_64-3.9/MySQLdb/_mysql.o -m64
    MySQLdb/_mysql.c: In function '_mysql_row_to_dict_cached':
    MySQLdb/_mysql.c:1340:5: error: 'for' loop initial declarations are only allowed in C99 mode
         for (unsigned int i=0; i<n; i++) {
         ^
    MySQLdb/_mysql.c:1340:5: note: use option -std=c99 or -std=gnu99 to compile your code
    error: command '/usr/bin/gcc' failed with exit code 1
    ----------------------------------------
ERROR: Command errored out with exit status 1: /home/cesc/envme/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-7imlhj3_/mysqlclient_4abebc3dfb814f09b6c8b217e744025e/setup.py'"'"'; __file__='"'"'/tmp/pip-install-7imlhj3_/mysqlclient_4abebc3dfb814f09b6c8b217e744025e/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-usi8p1fw/install-record.txt --single-version-externally-managed --compile --install-headers /home/cesc/envme/include/site/python3.9/mysqlclient Check the logs for full command output.

I've done these things

sudo yum install python3-devel mysql-devel gcc

I guess the problem may exist here

    MySQLdb/_mysql.c:1340:5: error: 'for' loop initial declarations are only allowed in C99 mode
         for (unsigned int i=0; i<n; i++) {
         ^
    MySQLdb/_mysql.c:1340:5: note: use option -std=c99 or -std=gnu99 to compile your code
    error: command '/usr/bin/gcc' failed with exit code 1

could you tell me how to run pip3 install with -std=c99 or any other solutions?

[daifengqi]

However, it will success when specify the version:

pip3 install mysqlclient==1.4.5