feat: small command line helpers for quick tests

pybind11/__main__.py

@@ -3,8 +3,16 @@
 import argparse
 import sys
 import sysconfig
+from pathlib import Path
 
-from .commands import get_cmake_dir, get_include, get_pkgconfig_dir
+from .commands import (
+    get_cflags,
+    get_cmake_dir,
+    get_extension,
+    get_include,
+    get_ldflags,
+    get_pkgconfig_dir,
+)
 
 
 def print_includes() -> None:
@@ -41,11 +49,43 @@ def main() -> None:
         action="store_true",
         help="Print the pkgconfig directory, ideal for setting $PKG_CONFIG_PATH.",
     )
+    parser.add_argument(
+        "--cflags",
+        action="store_true",
+        help="Print the simple compile flags",
+    )
+    parser.add_argument(
+        "--ldflags",
+        action="store_true",
+        help="Print the simple link flags",
+    )
+    parser.add_argument(
+        "--embed",
+        action="store_true",
+        help="Show embed version instead of extension",
+    )
+    parser.add_argument(
+        "--file",
+        type=Path,
+        help="Print the suggested compile line for a given file",
+    )
     args = parser.parse_args()
     if not sys.argv[1:]:
         parser.print_help()
-    if args.includes:
+    if args.cflags or args.file:
+        print(get_cflags(), end=" " if args.file else "\n")
+    elif args.includes and not args.file:
         print_includes()
+    if args.file:
+        print(args.file.name, end=" ")
+    if args.ldflags or args.file:
+        print(get_ldflags(args.embed), end=" " if args.file else "\n")
+    if args.file:
+        if args.embed:
+            print("-o", args.file.with_suffix(""))
+        else:
+            print("-o", args.file.with_suffix(get_extension()))
+
     if args.cmakedir:
         print(get_cmake_dir())
     if args.pkgconfigdir:

pybind11/commands.py

@@ -1,8 +1,16 @@
 import os
+import sys
+import sysconfig
+from typing import List
 
 DIR = os.path.abspath(os.path.dirname(__file__))
 
 
+def _getvar(varname: str, fmt: str = "{}") -> List[str]:
+    var = sysconfig.get_config_var(varname)
+    return [fmt.format(var.strip())] if var else []
+
+
 def get_include(user: bool = False) -> str:  # pylint: disable=unused-argument
     """
     Return the path to the pybind11 include directory. The historical "user"
@@ -35,3 +43,50 @@ def get_pkgconfig_dir() -> str:
 
     msg = "pybind11 not installed, installation required to access the pkgconfig files"
     raise ImportError(msg)
+
+
+def get_cflags() -> str:
+    """
+    Gets the compile flags needed for a simple module.
+    """
+
+    flags = f"-I{sysconfig.get_path('include')} -I{sysconfig.get_path('platinclude')} -I{get_include()}"
+    cflags = sysconfig.get_config_var("CFLAGS")
+    if cflags:
+        flags += " " + cflags
+        flags += " -std=c++11"
+    return flags
+
+
+def get_ldflags(embed: bool) -> str:
+    """
+    Get the linker flags needed for a simple module.
+    """
+
+    flags = _getvar("LDFLAGS")
+
+    if embed:
+        flags += _getvar("LIBIDR", "-L{}")
+        shared = sysconfig.get_config_var("Py_ENABLE_SHARED")
+        if shared and shared != "0":
+            flags += _getvar("LIBPL", "-L{}")
+        pyver = sysconfig.get_config_var("VERSION") or ""
+        flags += [f"-lpython{pyver}{sys.abiflags}"]
+
+        flags += _getvar("LIBS")
+        flags += _getvar("SYSLIBS")
+    else:
+        if sys.platform.startswith("darwin"):
+            flags += ["-undefined dynamic_lookup", "-shared"]
+        elif sys.platform.startswith("linux"):
+            flags += ["-fPIC", "-shared"]
+
+    return " ".join(flags)
+
+
+def get_extension() -> str:
+    """
+    Get the extension suffix on this platform
+    """
+
+    return sysconfig.get_config_var("EXT_SUFFIX") or ""